The increasing congestion of city streets from rapid growth of automative traffic has created a need for more and more sophisticated demand-responsive traffic control systems. Typically, cities have filled this need by tying traffic lights on major thoroughfares into a control center in which computer-assisted technicians can observe traffic through strategically placed remote-controlled video cameras and/or traffic counters, and then adjust traffic light cycles to move the maximum number of vehicles with the least delays.
Increased automation of this process requires that the control center be supplied with precise, real-time computer-readable data regarding the movement of vehicles in a plurality of lanes and directions. To some degree, this can be accomplished by systems using inductive loop sensors in the pavement, but such systems are limited in their sensing ability and area coverage, are expensive and are subject to mechanical damage.
A need therefore exists for a simple, relatively inexpensive monitoring system that can be quickly installed in an out-of-the-way place adjacent a roadway; which does not require the sawing of wire-carrying grooves into the roadway, thereby reducing installation cost and premature wearing of the road surface; and which provides simultaneous digitized real-time information on the position, speed and direction of all vehicles in the area of interest in and around the intersection.